It has been studied that a common lithium-ion secondary battery is applied to a vehicle-mounted power supply for hybrid automobiles, plug-in hybrid automobiles, electric vehicles and the like, and large-sized equipment such as a stationary power supply for storing power.
When the common lithium-ion secondary battery is applied to large-sized equipment, it is important to increase the battery in safety. The lithium-ion secondary battery is likely to leak a liquid and generate gas because it employs a non-aqueous electrolyte solution.